The Legacy Digital Private Branch Exchange (PBX) Has Reached the End of Its Life Cycle

The Private Branch Exchange (PBX) has been a important component of enterprise voice networks for many years. The PBX facilitates local in-company dialing, local calls outside the premises, and long distance calls.

Like the public telephone network switches but in a smaller package, switches are at the heart of carrier central offices. All calls are supported by the switch fabric for the duration of the call. Fabrics are engineered to minimize the probability of getting a busy signal and offer dial tone to those extensions reserving the limited call fabric.

Since the introduction of the digital PBX in the early 1980s, PBXs have been enhanced with adjunct processors for voice messaging (c.1985), Automatic Call Distribution (ACD) for rudimentary call center operations, or interactive voice response (IVR) servers used by specific communications applications or as a preprocessor of incoming call center calls. Services like these are driven through the PBX as the local focal point of telephony service.

The PBX is reaching the end of its lifecycle due to the emergence of two new product categories—IP-PBX and SIP-PBX. The IP-PBX value proposition is that it offers easier user administration and advanced applications. SIP-PBX users rapidly gain market share while the PBX market declines.

3Com® NBX® and VCX™ solutions were the first products in each of these categories to be marketed.